Electrochemical Deposition of Aluminum at Vitreous Carbon in a Room-Temperature Molten Salt

In 1.2 : 1.0 acidic melts, reduction of aluminum at -0.25 V (peak potential for reduction process) results in nonuniform coverage by aluminum for passage of 6 mC charge at a 0.07 cm vitreous carbon electrode. Although this charge corresponds to roughly 200 atomic layers of aluminum, SEM studies have shown that rather impure aluminum deposits occupy only a small fraction of the elect rode surface under these conditions. Chronoamperometric studies have shown that the deposited aluminum can be nearly quantitatively removed by a potential excursion to +0.50 V. Continuous deposits of aluminum are obtained when higher charges (800 mC) are used. These results are in general agreement with behavior observed at carbon surfaces in other work (1,2).